I just bought a new 2011 CVO Street Glide with a factory 110 motor. Have always used standard 20/50 oil. Being told to use the new syn oil on the 110 motor as this is the oil it comes with from the factory. The owners manual says the service interval is every 5k. I have always changed my oil every 2.5k. With the extra cost of syn oil should I still change the oil every 2.5K or is it ok to wait and go 5K between changes? Also, I always change the transmission and primary every 5k but with syn oil can I go 10K as stated in the owners manual?